The present invention relates to a method of ordering products.
More specifically, the present invention relates to a method of ordering products as they are fed onto a machine.
The present invention is particularly advantageous for use in the food packing industry, for packing products such as chocolates or similar, to which the following description refers purely by way of example.
In the food packing industry, products are supplied to a machine featuring an input conveying device having a number of conveying elements, which are fed at a given rate and with a given timing through a loading station where each receives a respective product.
The products are normally supplied in an orderly manner to the conveying device by means of a supply line, of which the conveying device forms the end element. Known supply lines normally comprise an ordering device for feeding a succession of products in a given traveling direction at said frequency, and for gradually bringing the products into contact with one another to form a continuous column of products for supply to a pickup station; and a transfer device extending between the pickup and loading stations, and which feeds the products to the loading station in time with said conveying elements.
The ordering device of known supply lines of the above type is normally defined by a conveyor belt, while the transfer device is normally defined by a wheel mounted for rotation about an axis crosswise to the traveling direction, and having a succession of equally spaced peripheral suction seats alternating with respective peripheral blow openings, and which are fed through the pickup and loading stations in time with the conveying elements. Each suction seat provides for engaging and removing the first product in the column from the pickup station in time with a respective conveying element, while the peripheral blow openings suspend removal of the products from the pickup station and temporarily arrest the whole column if the first product in the column is already located at the pickup station. As temporary stoppage of the column is not accompanied by a corresponding stoppage of the conveyor belt, this slides beneath and gradually damages the products.
To eliminate the above drawback, more recent transfer devices feature, in place of the suction seats, a number of orientable heads, each having a respective gripping element, and each orientable in relation to the traveling direction of the products by means of a control unit controlled by a photocell located at one end of the conveyor belt to detect transit of the products. On receiving a product transit signal, the control unit calculates the difference between the position of the product and the position of the respective gripping element in relation to the pickup station, and so orients the head as to advance or delay passage of the gripping element through the pickup station.
Though fairly efficient, orientable gripping heads of the type described are complex in design, expensive to produce, and require sophisticated operation control devices.